The objective of this study was to compare cardiorespiratory responses to exercise among older Qigong participants, Tai Chi Chuan (TCC) practitioners and normal sedentary controls during cycle ergometry. Thirty-six community-dwelling men with a mean age of 59.1 +/- 6.6 years participated in this study. Each group (Qigong, TCC and control) included 12 subjects with matched age and body size. The Qigong group practiced Qigong regularly for 2.3 +/- 1.5 years; the TCC group practiced Yang TCC for 4.7 +/- 2.3 years. Heart rate (HR) responses were measured during the practice of Qigong and TCC. Additionally, breath-by-breath measurement of cardiorespiratory function was performed during the incremental exercise of leg cycling. The mean HR during Qigong and TCC practice was 91 +/- 5 bpm and 129 +/- 7 bpm, respectively. At the peak exercise and the ventilatory threshold (VeT), TCC group displayed highest oxygen uptake (VO2), O2 pulse and work rate among the three groups. The Qigong group also showed higher oxygen uptake and O2 pulse than the control group. At the same relative exercise intensity, the Qigong group had the highest tidal volume among the three groups. In conclusion, Qigong and TCC show a beneficial effect to aerobic capacity in older individuals, but TCC displays a better training effect than Qigong due to its higher exercise intensity. However, Qigong can enhance breathing efficiency during exercise due to the training effect of diaphragmatic breathing.